def create_ephemeral_message(ttl: int,
ttr: int,
addr_from: bytes,
kyber_pk: bytes,
kyber_sk: bytes,
receiver_kyber_pk: bytes,
prf512_seed: bytes,
seq: int,
data: bytes,
nonce: int):
sender_kyber = Kyber(kyber_pk, kyber_sk)
sender_kyber.kem_encode(receiver_kyber_pk)
aes256_symkey = sender_kyber.getMyKey()
aes = AES(aes256_symkey)
ephemeral_data = EphemeralMessagePayload.create(addr_from, data)
encrypted_ephemeral_message = EncryptedEphemeralMessage()
encrypted_ephemeral_message._data.msg_id = RNG.generate(prf512_seed, seq)
encrypted_ephemeral_message._data.ttl = ttl
encrypted_ephemeral_message._data.ttr = ttr
encrypted_ephemeral_message._data.nonce = nonce
encrypted_ephemeral_message._data.payload = aes.encrypt(ephemeral_data.to_json())
return encrypted_ephemeral_message
def create_ephemeral_channel(msg_id: bytes, ttl: int, ttr: int,
addr_from: bytes, kyber_pk: bytes,
kyber_sk: bytes, receiver_kyber_pk: bytes,
dilithium_pk: bytes, dilithium_sk: bytes,
prf512_seed: bytes, data: bytes, nonce: int):
sender_kyber = Kyber(kyber_pk, kyber_sk)
sender_kyber.kem_encode(receiver_kyber_pk)
enc_aes256_symkey = bytes(sender_kyber.getCypherText())
aes256_symkey = sender_kyber.getMyKey()
aes = AES(bytes(aes256_symkey))
sender_dilithium = Dilithium(dilithium_pk, dilithium_sk)
ephemeral_data = EphemeralChannelPayload.create(addr_from, prf512_seed,
data)
ephemeral_data.dilithium_sign(msg_id, ttl, ttr, enc_aes256_symkey, nonce,
sender_dilithium)
encrypted_ephemeral_message = EncryptedEphemeralMessage()
encrypted_ephemeral_message._data.msg_id = msg_id
encrypted_ephemeral_message._data.ttl = ttl
encrypted_ephemeral_message._data.ttr = ttr
encrypted_ephemeral_message._data.channel.enc_aes256_symkey = enc_aes256_symkey
encrypted_ephemeral_message._data.nonce = nonce
encrypted_ephemeral_message._data.payload = aes.encrypt(
ephemeral_data.to_json().encode())
return encrypted_ephemeral_message
def test_exchange_keys(self):
alice = Kyber()
bob = Kyber()
# Alice sends her public key to Bob
alice_public_key = alice.getPK()
# Bob receives the public key, derives a secret and a response
bob.kem_encode(alice_public_key)
cypherText = bob.getCypherText()
# Bob sends the cyphertext to alice
valid = alice.kem_decode(cypherText)
# Now Alice and Bob share the same key
alice_key = alice.getMyKey()
bob_key = bob.getMyKey()
self.assertTrue(valid)
self.assertEqual(alice_key, bob_key)
class Kyb():
def __init__(self, PK=None, SK=None):
if not PK or not SK:
self.k = Kyber()
else:
self.k = Kyber(PK, SK)
self.PK = self.k.getPK()
self.SK = self.k.getSK()
def kem_encode(self, kyber_pk):
self.k.kem_encode(kyber_pk)
self.ciphertext = self.k.getCypherText()
self.shared_secret = self.k.getMyKey()
return self.ciphertext, self.shared_secret
def kem_decode(self, ciphertext):
if self.k.kem_decode(ciphertext) == True:
self.shared_secret = self.k.getMyKey()
return self.shared_secret
else:
return False